The Bonnanaro culture is a protohistoric culture that flourished in Sardinia during the 2nd millennium BC (1800–1600 BC), considered to be the first stage of the Nuragic civilization. It takes its name from the comune of Bonnanaro in the province of Sassari where in 1889 the eponymous site was discovered.
The Bonnanaro culture is divided chronologically into two main phases:
According to Giovanni Lilliu the people who produced this culture probably originated in Central Europe and the Polada culture area. From a material culture point of view, the Bonnanaro culture shows influences of the preceding pan-European Bell Beaker culture and of the Polada culture from northern Italy.
Bonnanaro sites, mostly burials, are scattered throughout Sardinian territory, with a higher concentration in the mining regions of Nurra and Sulcis-Iglesiente and in the Campidano. Ceramics were smooth and linear without decorations and characterized by handles. Numbers of metal objects increased and the first swords of arsenical bronze appeared.
Only four settlements of this culture are known: Su Campu Lontanu Florinas, Sa Turricula Muros, Costa Tana Bonarcado and Abiti Teti. The houses had a base of masonry while the roof was made of wood and branches.
It is still uncertain whether the first "protonuraghi" or "pseudonuraghi" were built at this time, or in the successive Sub-Bonnanaro culture (or Bonnanaro B) of the middle bronze age (1600–1330 BC). The Proto-Nuraghi were megalithic edifices which are considered the precursors of the classic Nuraghi. They are horizontal buildings characterized by a long corridor with rooms and cells.